Process for aerating liquid.



LLBERG.

uQum.

. M. KRAUT l F.

PRCESS FOR AER APPLmArmN man No Patented Apr. 2, 1918.

2 sHEUs-SHEEI l.

M. KRAu La f. B. KOLLBERG.

PROCESS FDR AERATING LIQUID.

APPLICAUON FILED NOV. 8. |916.

FREDERICK B. KOLLBERG, OF BISBIIE. ARIZONA.

CALIFORNIA, ASSIGNORS T0 SOUTHWESTERN RATION OF CALIFORNIA.

ANI) MAX KRAUT, 0F LOS ANGELES, ENGINEERING COMPANY, A CORPO- PROCESS FOR AERATING LIQUID.

Specication of Letters Patent.

Patented Apr. 2, 1918.

Application tiled November 8, 1916. Serial No. 130,170.

To all whom it may concern: Bc it known that wc, FREDERICK B. Koni.- iiaiic, residing at Bisbee, in the county of Cochise, State of Arizona, and Max KRAUT, residing at Los Angeles. in the county of Los Angeles, State of California, both citizens of the United States of America, have invented new and useful Improvements in Processes of Aerating Liquid, of which the following is a specification.

This invention relates to a process of aer ating liquid and is especially adaptable for of any great amount o By oui-:process we expose a maximum Yof sur-A aeration of pulp in mineral separation proc- It is anobject of this invention to r0.- vide 'a process whereby air or other uid may be introduced into liquid to foi-m a froth,-w,ith a minimum of energy. .Heifetfore mechanical xigitation'of pulp in-otation'macliines for the purposejof pro- -tycry ineiiicient-,-be

energy in moving fthe air.

cai'iseoflthe wastage o thev pulpv about without accomplishing faeeo'f the lpulp to the air, introduce the air intoja passage, inove the pulp over the air,

` thereby forming' bubbles and moveJ the bubbles .andpulp from the passage.

A means for carrying out this rocess is disclosed in our application, S. 107,202 filed July .1, 1916, for reissue of 'Patent 1,174,737, Mar. 7, 1916, in which the {iotation separation chambers are claimed, and in a co-pending application S. N. 130,169, filed Nov. 8, 1916, in which the aeration apparatus is claimed. l -f the drawings, Figure 1 is a vertical transverse section through the aeration chamber of the a paratus.

' Fig. 2 is a, detail sectional fragment of the preferred form of aci-ating drum shown in i 1. gig. 3 is a. detailsectional view of a fragment of a modified. form of aeration drum. Fig. 4 is a vertical central longitudinal section through the aeration chamber of the' apparatus Fig. 5 is a developed fragmentary diagrammatic view in section of the preferred form of aci-ating drum and casing. Fig. 6 is a diagrammatic view similar to Fig. 5

of the modified forni of aerating drum, shown in Fig. 3 and casing.

Referring more particu arly to the drawing, an elongated Substantially rectangular a fi ation chamber 1 is mounte upon a suitable supporting framework 2. Extending alon one side of the chamber 1 and substantially coextensive,therewith, is a frothing chamber 0r box 3, which is open at its upper side and provided with an inclined bottom 4. Communicating with the head end of the aeration chamber 1 is an entrance opening or passage 5, through which the pulp to be treated'is introduced into said chamber. Leading from the bottom of the frothing chamber 3 at the oppositeor tail end of the machine is a discharge pipe, not

shown, through which y,tailings are d ischarged.

Forned in one side of 'the chamber 1 ad- 7 is a ha board or flange 8 which serves toA deflect the pulp' discharged through said pas sage outwardly. Leading from the bottom of the frothing chamber 3 to the bottom of .the aeration. chamber 1 are s aced return openings 9 which'are controlle by a sliding gate v10 having a notched lower end to correspond with'said openings 9.

Arranged in the aeration chamber 1 is the aeration element or drum 1-1. Said drum consists of a cylindrical wall 12 which is bolted as shown to spiders 13 fixed to a" shaft 14 extendin Vcentra chamber an having its ends suitably mounted in bearings provided at the ends of said chamber. Air may freely circulate through,

the drum around the spider arms. The cylindrical wall 12 is rovided with slots 15 which extend theret rou h and communicate with the interior o the drum. The outer surface of the wall 12 is preferably made irregular in form, as clearly shown in the various figures of the drawing by means of a plurality of closely spaced lon'tudinally extending rilles 16 as shown in ig. 2

lythrough the aeration v lof the 'pulp will result.

The rtlles 16 serve to entrap air therebetween and pocket or hold the same while the ulp slips tbereover. In Fig. 3 the a1r 1s lield by frictional contact with the surface of the drum and pulp slips thereover.

Provided in the chamber 1 at the lower edge of the outlet opening 8 is an inwardly `projecting flange 17 which serves to direct toward said out et opening the thin sheet of pulp centrifugally thrown from the aeration drum. Communicating with the upper end of the aeration chamber is a plurality of air supply pipes 18, passage through which is controlled by valves 19. Arranged in chamber 1 below the lower end of the air supply pipe 18 swa dellecting board 20 so arranged that the air which 1s supplied to the chamber 1 will be introduced into said chamber and adjacent the criphery of the aeration element tangential y thereto and in a direction toward the outlet opening 6. The thin sheet of pulp thrown from the aeration drum induces air from pipes 18 increasing the aeration of the pulp.

Oil. supply pipes 21 are empoyed, communicating with the interior of the chamber, and are cgntrolled by valves 22. A casing 23 is spaced from and about the rear portion of the drum 11 as indicated in Fig. 1, thereby providing an aeration space 24 of arcuate section through which theV pulp travels end in which it is aerated. The casing4 23 at its lower part is extended to the tloor of the aeration chamber in a direction tangential to the aeration drum. This con# struction assists-'in the 4direction .of pulp to the inlet'ofA the aeration space. r

ln operation the aeration drum 11. is rotated at u suitablc speed. The pulp level inside the aeration chamber is maintained means of the ate 10 at such a height that the outer sur acc ef the aeration drum is slightly immersed in the pulp, the latter being slightly higher than a tangentto the lower surface Vof the drum. The level is maintained justsuflieient to fill the entrance to the aeration spare 24. A greater height is not desirable, as agitation and beating This is ineffective in producing aeration and results in a loss of power.. ,Excessive beating of the pulp may also result.- in em'ulsileation which is found to be undesirable.

In the rotation of the drum the adhesion ofthe pulp to the drum causes a flow of the pulp ai high velocity through theaeration space :4. 'lhis producps a high velocity bead and a low pressure head, the pressure head decreasing with the increase of velocity head. By imparting sufficient velocity to the pulp the ressure head may be decreased to less t an atmospheric pressure, and air induced through the perforations 15. Tt will be noted, that air may readily enter the interior of the drum through the hollow drip cups at each end of the chamber 1. Air is thereby introduced into the pulp and conuninglcd therewith. thrown oil the surface of the drum at the upper end of casing 23, due to the centrifugal action and encounters theapron 1T, being directed thereby into the outlet opepng 6; air is also induced through the pipe 18 into the aerating chamber, mixing with the pulp as it is thrown from the drum.

As the pulp passes into the passage 7, it moves downwardly into the frothing chambert The froth overflows from the top ofthe frothing chamber carrying with it mineral", and the pulp sinks to the bottom for retreatment on return through opening 9 to the air chamber.

ln mechanically actuated flotation machines especially of the horizontal type, bearings are neet-ssa ry for the. shaft carrying the agitators. These bearings, when below the level of the pulp, must be packed to prcvent the pulp from leaking therethrough. Due to the sand and other gritty material in the. pulp. the hearings and shaft rapidly wear and must he, repaired and re laced. Our lmachine is not subject to such di culty, as the bearings for the aeration drum shaft are. not. in contact with the ulp.

In the aeration devicc,ysliown herein, air is induced lthrough slots 15, meets thesur- 1faire of the thinstream of -pnlp whichis moved by the drinn through passage 24, because of adhesive and viscous action. There is a slippage of pulp relative to the drum, and the air entering the passage slips along the surface of the drum imckelingilseli between riilles 16. inthe preferred lform of drum, or being held by thefrictional action of the drum surface in tliermodified form,

Aeratcd pulp isV shown in Fig. While held thus. the pulp draws a film thereover and bubbles are formed. The pulp and bubbles are then carried by the drum to the discharge exit of the passage 24 and thrown from the drum Ihrougi opening 6 into the frothing cham her. This machine does not depend upon agitation for aen-ating of 'the pul i as a very slow rotation olthe druml will result in aeration.

In Fig. 5, the pulp passing through aeration space 24 is shown with air poekcted between the rillles 16, the relative movement of the pulp'and the wall 12 of the drinn being indicated by arrows. rl`he moving wall 12 carries the pocketed bubbles to the outlet of space 24 and discharges the pulp and bubbles in the form of a pnl lnfFig. 6 the air is drawn through periiirations 15 into the space 24, being held by frictional cpntact with wall 12. Bubbles are thus formed and the pulp and bubbles moved through space 24 to the outlet.

What We claim is:

1. A process for separating minerals,

' menue which consists in moving u liquid pulp along a partially cylindrical passage, injecting an' into said passa e upon the surface ofv said liquid pulp, hfilding said air in said passage so that the liquid pulp passes theref over and draws a film thereof over saidair thereby forming bubbles from said liqyid, pulp, arid moving said bubbles along said passage 2. process for separating minerals, which consists in moving a liquid pul containin a percentage of oil therein a ong a parta ly cylindrical passage, placing the surface of said liquid pulp in contact with air, inducing the same into the essage upon 15 the surface of said liquid p pocketing the air between the Surface of said liquid pulp and a wall of seid passage, so that the liquid pulp passes thereover and draws a.

film thereof over said pocketed aix', thereby 20 FREDERICK B. KOLLBERG. MAX KRAUT. 

